Fabricated brake beam truss and method of making same

ABSTRACT

A FABRICATED BRAKE BEAM TRUSS MADE FROM STANDARD ROLLED STEEL SECTIONS WELDED TOGETHER TO PROVIDE TO JOINT OF MAXIMUM STRENGTH AND FLEXIBILITY WITH MINIMUM STRESSES THEREIN.

United States Patent Frank Kenneth Veasman Hamburg, N.Y. 791,607 Jan. 16, 1969 June 28,1971

Buffalo Brake-Beam Company Inventor A ppl. No. Filed Patented Assignee FABRICATED BRAKE BEAM TRUSS AND METHOD OF MAKING SAME 14 Claims, 14 Drawing Figs.

Int. Cl ..B6lh13/36 Field of Search 188/2191,

References Cited UNITED STATES PATENTS Busch...... Busch Whitney Harder Busch Primary Examiner-Duane A. Reger AttorneyMorrison, Kennedy & Campbell ABSTRACT: A fabricated brake beam truss made from standard rolled steel sections welded together to provide a joint of maximum strength and flexibility with minimum stresses therein.

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PATENTEU JUN28 I971 3.581791 SHEET 1 [1F 3 T1 qJL- PATENTEU JUN28 l9?! SHEET 3 OF 3 FABRICATED BRAKE BEAM TRUSS AND METHOD OF MAKING SAME The brake beam trusses of the prior art were usually made by rolling the compression and tension members together as one member and then cutting the compression member free of the tension member in all but the areas of the junctions at opposite ends, after which the tension member was bent into proper shape. However, this method of manufacture is limited by the choice of rolled sections that could be produced as well as the practical and economic means of separating the shaped sections after rolling. This method of producing the beam trusses is therefore expensive due to the number of type of operations involved.

The brake beam truss of the instant invention is fabricated of standard rolled steel sections and involves no cutting whatsoever. The truss design is unique in that it also provides a welded joint that has both structural strength and rigidity as well as flexibility. The rigidity is provided by the more than adequate fusion of metal along the line of junction of the tension and compression members, while the flexibility is brought about by the selection of the proper shape for the tension member to allow maximum flexure with minimum stresses due to flexing. The use of standard rolled shaped permits the selection of tension and compression members having the optimum in shapes and simplifies the fabrication of these members into an integral or one-piece truss. The advances in the development of welding technology has been such that it is now possible to produce welds that possess great strength and rigidity but allowing great flexibility. The joint being used fulfills the basic requirement of a structural joint in that it has the strength to develop the full load carrying capacity of the joined structural members (tension and compression), and moreover has the flexibility in the joint itself to eliminate secondary stresses and yet retain the sound basic principles incorporated in a one-piece brake beam truss.

Accordingly, it is a primary object of the invention to provide flexibility in the areas of the joints and still provide maximum stiffness in a plane perpendicular to the truss. The tension member is rectangular in cross section with its ends forged so that the thickness of the member is greatly increased throughout the joint area to result in extreme rigidity throughout the joint on welding. The tension member will still have its greater dimension in a plane perpendicular to the plane of the brake beam truss throughout the rest of its length to result in maximum rigidity to the truss against forces that are applied perpendicular to the truss.

A second object of the invention is to provide ideal stress distribution along the line of juncture of the tension and compression members.

A third object of the invention is to contour the ends of both the tension and the compression members of the truss by means of forging, welding, etc., to avoid stress concentration in the area of the welded joints.

A fourth object of the invention is to select rolled steel sections for the tension and/or compression members that will allow flexing without introducing excessive stresses in the truss. The flexing herein referred to is caused by a change in angle between the two members with respect to each other when load is applied to'the truss. It is only by designing the welded joint to take care of these additional secondary stresses that failure thereof could be avoided. In the design of the truss of the instant invention, these secondary stresses are taken care of by the flexing of the tension member due to its shape and mode of welding. In this manner, the stresses in the welded joint are not only reduced but in addition the use of lighter sections is permitted to reduce the weight of the truss. Weight reduction is of course an important factor in the design of a brake beam truss as well as an electrical advantage.

A fifth object of the invention is to provide welded joints between the tension and compression members of such design that the lines of application of the forces generated therein pass along controid of the members and through the center of the structural welded joints which unite the two members. This should be adhered to rather religiously in order to provide even stress distribution in the weld itself.

- ments of the invention which follows:

In the drawings:

FIG. 1 is a top view of a brake beam truss fabricated from rolled flat bar stock (tension member) and T-section rolled stock (compression member) and clearly shows the welded ends;

FIG. 2 is an enlarged cross section taken on the line 2-2 of FIG. I and more clearly brings out the welding techniques employed in assembling the truss;

FIG. 3 is an enlarged cross section taken on the line 3-3 of FIG. I and clearly shows the T-section with the forged end of tension member welded thereto;

FIG. 4 is a top view of a brake beam truss fabricated from rolled flat bar stock (tension member) and rolled channel stock (compression member) and again clearly shows the welded ends;

FIG. 5 is an inside face view of the left-hand end of the brake beam truss of FIG. 4 and brings out the cutting and welding techniques employed in modifying the truss at the ends;

FIG. 6 is a section through the channel-shaped compression member taken along the line 6-6 of FIG. 4 and shows the channel section as it is throughout its main center portion;

FIG. 7 is a section through the channel-shaped compression member taken along the line 7-7 of FIG. 4 and shows the modification that is made to the ends of the compression member preparatory to welding the tension member thereto;

FIG. 8 is a section through the channel-shaped compression member taken along the line 8-8 of FIG. 4 and shows the further modifications that are made to the ends of the compression member before being welded to the tension member;

FIG. 9 is a top view of a brake beam truss fabricated from rolled flat bar stock (tension member) and rolled channel stock (compression member) and again clearly shows the welded ends but in this instance the modification to the channel is slightly different from that disclosed in FIG. 4;

FIG. 10 is an inside face view of the left-hand end of the brake beam truss of FIG. 9 and brings out the cutting and welding techniques employed in modifying the truss at the ends;

FIG. 11 is a section through the channel-shaped compression member taken along the line Il-Il of FIG. 9 and clearly shows the channel section as it, is throughout its major center portion;

FIG. 12 is a section through the channel-shaped compression member taken along the line 12-12 of FIG. 9 and clearly 7 shows the modification that is made to the ends of the compression member preparatory to welding the tension member thereto;

FIG. 13 is a section through the channel-shaped compression member taken along the line 13-13 of FIG. 9 and shows the further modifications that are made to the ends of the compression member and also clearly shows the tension member welded thereto by means of structural welds; and

FIG. 14 is a section through the channel-shaped compression member taken along the line 14-14 of FIG. 9 and shows the further modifications that are made to the ends of the compression member and also clearly shows the tension member welded thereto by means of face welds.

The brake beam truss 10 shown in FIGS. 1, 2 and 3 is fabricated from flat rolled stock used for the tension member 11 and a rolled T-section used for the compression member 12, while the strut 13 is formed froma hollow rectangular section suitably contoured and welded in place to result in maximum lightness and still give extreme stiffness. The tension member II presents a bow-shaped major portion of oblong cross section dimensioned for a certain amount of flexibility in a facewise direction. Themajor portion has its greater dimension disposed at right angles to the longitudinal axial plane of the truss structure to impart maximum rigidity to the truss structure against forces that are applied perpendicular to the longitudinal axial plane of said structure. The'compression member 12 presents longitudinally extending web and leg portions disposed at right angles to each other. The web has its greater dimension disposed at right angles to the longitudinal axial plane of the truss structure to give maximum rigidity to the truss structure against forces that are applied perpendicular to the longitudinal axial plane of the truss structure. The leg portion of the compression member has its greater dimension disposed parallel to the longitudinal axial plane of the truss structure to give maximum rigidity to the structure against forces that are applied thereto in said plane. The tension member 11 also presents at its opposite ends straight elongated flange portions 1 la of oblong cross section lying in the longitudinal axial plane of the truss structure and welded to the opposite ends of the compression member 12 to provide a strong rigid welded joint between the tension member 11 and the compression member 12. The flexibility of the major portion of the tension member 11 due to its oblong cross section eliminates objectionable secondary stresses in the member itself as well as in the welded joint between the tension member 11 and the compression member 12. In welding the tension member 11 to the compression member 12 the tension member 11 is shaped on its two bottom edges for a distance shown on the drawing indicated by the numeral 14, while the remaining distance shown by the numeral 15 does not need to be shaped. The welding therefore that is done in the area designed under the numeral 14 may be a structural weld or a fillet weld and possesses great strength and rigidity, while the face welded area which is beyond the structural or fillet weld area is simply put there to present an area for the mounting of wear plates and brakeshoes. The wear plates as normally used would be the same as that shown in the US. Pat. No. 2,170,122 to Busch or castings ofproper shape.

The design of the welded joint between the tension member 11 and compression member 12 is such that the line of action of the force applied when the truss is loaded passes through the center of the welded area and is shown by dotted lines on FIG. 1. s

It will be noted that the straight elongated flange portions 11a of the tension member 11 are formed with heel portions 11b at the apices of the angles between the tension member and the compression member to distribute the stresses at the line of juncture of said members. In other words, each of the straight elongated flange portions Ila of the tension member 11 in the areas where they merge with the major portion of the tension member is curved or arched to provide flexibility in those areas and thus afford good distribution of the stresses imposed on the welded joint and prevent fatiguing and failure.

A typical beam truss design would be as follows with the tension member 11 being a rolled flat bar stock 2 inches wide and three-fourths inch thick with the ends forged down to liinches height and 1 inch width. The compression member 12 would be a rolled channel T-section commonly designated as 8.1. 3.51 and weighing 100 per foot of length. The strut 13 could be a 2 inch square --%inch thick walled tube. The parts would be assembled as shown in FIGS. 1, 2 and 3 to result in a superior designed brake beam truss which would be lighter and stronger and be more economical to fabricate.

In FIGS. 4, 5, 6, 7 and 8, the .brake beam truss is fabricated from flat rolled stock used for the tension member 21 and a rolled channel section used for the compression member 22 while the strut 23 is again formed of a hollow rectangular section welded in place. The ends of the tension member 21 are again forged to a given cross-sectional area at the ends the same as in FIGS. 1, 2 and 3 and the tension member then welded to the compression member in the same manner as in FIGS. 1 to 3. The channel-shaped compression member 22 is modified at the ends by cutting the two legs 24 and 25 away from the web and shaping them as shown in FIG. 5, and then welding them in place and contouring the web, all as shown in FIG. 8. It is also possible in this design to eliminate the shaping of the ends of the tension member 31 and use a suitable number of passes of fillet welds to result in maximum strength and flexibility. This design allows the brakeshoes and wear plates to be mounted on the beam and the resultant cross section gives maximum strength to the compression member in that region.

In FIGS. 9, 10, ll, l2, l3 and 14, the brake beam truss 30 is fabricated from flat rolled stock used for the tension member 31 and rolled channel section used for the compression member 32 while the strut 33 is again formed of a hollow rectangular section welded in place. The ends of the tension member 21 are again forged to a given cross-sectional area at the ends and welded to the compression member as in FIGS. 1, 2 and 3. The channel-shaped compression member 32 is modified at the ends by cutting the two legs 34 and 35 away from the web and shaping them as shown in FIGS. l0, l2, l3 and I4 and then welding them in place with face welds. The web itself is partially removed at the end to provide mounting space for the wear plates and brakeshoes. Here again it will be noted that the channel section is actually changed to a T-section at the ends to maintain strength and stiffness in the compression member in those zones but still maintain flexibility. This design therefore results in structural strength and rigidity with extreme flexibility.

The brake beam truss of the instant invention is really a socalled "break through" in that it allows the truss to be completely fabricated from standard rolled sections. The design of the welded joint itself contains what are generally classed as unique features as will be described later but the joint fulfills the basic requirements of a structural or joint fillet as it has the strength to develop and use the full capacity of the joined structural members and still has the flexibility to eliminate objectionable secondary stresses therein and retains the sound basic principle of a one-piece brake beam truss of the prior art.

The basic features of the invention are as follows:

1. Flexibility in the area of the welded joint and maximum stiffness in the plane perpendicular to the truss. This is accomplished by using a rectangularly shaped tension member and forging the ends thereof to greatly increase the thickness thereof at the joints and produce rigidity therein; but the remaining length has its greatest (the original width) dimension in a plane perpendicular to the truss for maximum rigidity to the forces applied in this direction.

2. Rigidity in the areas of joining the tension and compression members.

3. Contouring or modifying of the ends ofone or both members to avoid stress concentration in the area of the welded joint.

4. Selection of one or both members to allow flexing without introducing excessive stresses in the welded joint.

Normally the joint must be designed to take care of these excessive stresses but in the design of the instant invention the excessive stresses are taken care of by allowing the tension member to flex to thereby eliminate any secondary stresses in the joint itself.

. The design of the joint between the tension and compression members is so arranged that the line of force application is projected through the center of the joint.

I claim:

1. A brake beam truss structure comprising a tension member made from rolled metal stock and presenting a bow-shaped major portion of oblong cross section dimensioned for a certain amount of flexibility in a facewise direction, said major portion having its greater dimension disposed at right angles to the longitudinal axial plane of the truss structure to give maximum rigidity to the truss structure against forces that are applied perpendicular to the longitudinal axial plane of said structure,

' a compression member made from rolled metal stock and presenting longitudinally extending web and leg portions disposed at right angles to each other,

LII

the web portion having its greater dimension disposed at right angles to the longitudinal axial plane of the truss structure to give maximum rigidity to the truss structure against forces that are applied perpendicular to the longitudinal axial plane of said truss structure,

and the leg portion of the compression member having its greater dimension disposed parallel to the longitudinal axial plane of the truss structure to give maximum rigidity to said structure against forces that are applied thereto in said plane,

said tension member also presenting at its opposite ends straight elongated flange portions of oblong cross section lying in the longitudinal axial plane of the truss structure and welded to the opposite ends of the compression member to provide a strong rigid welded joint between the tension member and the compression member,

the flexibility of the major portion of the tension member due to its oblong cross section eliminating objectionable secondary stresses in the member itself as well as in the welded joint between the tension member and the com pression member.

2. A brake beam truss structure according to claim 1, wherein the major portion of the tension member is in the form of a flat strap of rectangular cross section and having a width sufficiently greater than its thickness to provide a predetermined amount of flexibility in a facewise direction.

3. A brake beam truss structure according to claim 1, wherein the straight elongated flange portions of the tension member are formed by forging the rolled metal stock into the required shape before the tension member is joined to the compression member.

4. A brake beam truss structure according to claim 1, wherein the straight elongated flange portions of the tension member are formed with heel portions at the apices of the angles between the tension member and the compression member to distribute the stresses at the line of juncture of said members.

5. A brake beam truss structure according to claim 1, wherein each of the straight elongated flange portions of the tension member in the area where it merges with the major portion of said member is curved or arched to provide flexibility in that area and thus afford good distribution of the stresses imposed on the welded joint.

6. A brake beam truss structure according to claim 1, wherein the straight elongated flange portions of the tension member are each joined to the compression member by structural or fillet welds extending for a substantial distance from the inner end of the line of juncture of said members.

7. A brake beam truss structure according to claim 6, wherein the straight elongated flange portions of the tension member are each joined to the compression member by face welds forming an outer continuation of the structural or fillet welds.

8. A brake beam truss structure according to claim 1, wherein the compression member is formed from a T-shaped rolled metal section and wherein the straight elongated flange portions of the tension member are arranged in the longitudinal plane of the leg portion of the compression member and are joined by structural or fillet welds to the outer face of the web portion of said compression member.

9. A brake beam truss structure according to claim 1, wherein the compression member is formed from a channel shape rolled metal section having its leg portions, at its opposite ends, bent inwardly into face to face contact and welded to the straight elongated flange portions of the tension member.

10. A brake beam truss structure according to claim 9, wherein the web portion of the compression member is cut away in the region of bending of the leg portions to facilitate such bending and to expose the outer edges of the bent leg portions for contact with and welding to the straight elongated flange portions of the tension member.

11. A brake beam truss structure according to claim 9,

wherein the bent-in leg portions of the compression member are slitted throughout the bent-in area from the web portions of the compression member to provide in effect a T-shaped cross section in said area.

12. A brake beam truss structure according to claim I, wherein the leg portions of the compression member extend outwardly beyond the outer extremities of the web portion of said member to provide extensions for the mounting of wear plates and brakeheads.

13. A brake beam truss structure according to claim 1, including a strut member arranged between the tension member and the compression member at the central portions thereof and holding them in separated relation under tension and compression, respectively.

14. As a separate article of manufacture, a tension member for a brake beam truss structure as described in claim 1. 

